Composite articles containing or exhibiting a microstructured layer or columnar-structured layer have been disclosed in the art.
For example, U.S. Pat. No. 4,410,565 (Kitamoto et al.) discloses an article said to be useful as a magnetic recording medium, the article comprising a substrate, a thermoplastic prime-coating layer provided thereon, a ferromagnetic metal layer having columnar grains which at least partially penetrate into the prime coat from the top thereof and are integrated therewith. A method of making the same is also disclosed. Further, U.S. Pat. No. 4,588,656 (Kitamoto et al.) teaches a method of preparing an article said to be useful as a magnetic recording medium, the method comprising vapor depositing a thin ferromagnetic metal film having spaced-apart columnar grain structures onto a substrate, impregnating the spaces between the columnar grain structures with at least one organic monomer or oligomer in the liquid form, and polymerizing the monomer or oligomer at least in the spaces between the columnar grain structures, whereby the resulting polymer is integrated with the thin ferromagnetic metal film.
U.S. Pat No. 4,560,603 (Giacomel) teaches a method for making a high strength laminated composite-structured material comprising the steps of (a) providing whiskers having a characteristically preferred orientation in an electromagnetic field, (b) placing fibers in a substantially overlapping relationship having viscous material therebetween to form a composite matrix, (c) disposing the whiskers in the viscous material, (d) applying a magnetic field about the whiskers in a shape effective to selectively orient the whiskers in a preferred direction, and (e) curing the composite matrix to form a laminate, while at the same time retaining the whiskers in the desired direction.
U.S. Pat. No. 4,774,122 (Adler) discloses a resinous product having a resinous surface which is coatable with a metal layer so as to be bonded through an array of microdendrites. A method of making the same is also disclosed.
U.S. Pat. Nos. 4,812,352 and assignee's patent application, U.S. Ser. No. 07/271,930, filed Nov. 14, 1988, now U.S. Pat. No. 5,039,561 (Debe) teach an article comprising a substrate bearing a microlayer (microstructured-layer) which comprises uniformly oriented, crystalline, solid, organic nanometer-sized microstructures and a method of making the same. Further, U.S. Pat. Nos. 4,812,352 and U.S. Ser. No. 07/271,930 teach optionally conformal coating the microlayer and encapsulating the conformal-coated microlayer.
Kam et al. in "Summary Abstract: Dramatic Variation of the Physical Microstructure of a Vapor Deposited Organic Thin Film", J. Vac. Sci. Technol. A, 5, (4), July/August, 1987, pp. 1914-16, teach a vacuum deposition method for making organic microstructures (or whiskers).
Debs et al. in "Vacuum Vapor Deposited Thin Films of a Perylene Dicarboxide Derivative: Microstructure Versus Deposition Parameters", J. Vac. Sci. Technol. A, 6, (3), May/June, 1988, pp. 1907-11, teach a vacuum vapor deposition method for generating organic microstructures.
Debe et al. in "Effect of Gravity on Copper Phthalocyanine Thin Films III: Microstructure Comparisons of Copper Phthalocyanine Thin Films Grown in Microgravity and Unit Gravity", Thin Solid Films, 186, 1990, pp. 327-47, disclose organic microstructured surfaces grown by physical vapor transport in microgravity and on the earth's surface.
Sadaoka et al. in "Effects of Morphology on NO.sub.2 Detection in Air at Room Temperature with Phthalocyanine Thin Films", J. Mat. Sci., 25, 1990, pp. 5257-68, teach a method of growing nickel phthalocyanine whiskers by annealing a film of the same in air.
Dirks et al. in "Columnar Microstructure in Vapor-Deposited Thin Films", Thin Solid Films, 47, 1977, pp. 219-33, review methods known in the art for making columnar microstructures.
U.S. Pat. No. 3,969,545 (Slocum) discloses a vacuum deposition technique for making organic or inorganic microstructures. The microstructured surface is said to have excellent polarization characteristics over wavelengths from the visible to the infrared region.
Ohnuma et al. in "Amorphous Ultrafine Metallic Particles Prepared By Sputtering Method", Rapidly Quenched Metals, (Proc. of the Fifth Int. Conf. on Rapidly Quenched Metals, Wurzburg, Germany, Sep. 3-7, 1984), S. Steeb et al., eds., Elsevier Science Publishers B. V., New York, (1985), pp. 1117-24, teach microstructured surfaces made using ion etching and rf sputter etching of polymer surfaces.
U.S. Pat. No. 4,568,598 (Bilkadi et al.) teaches a composite sheet-like article comprising surface ridges or needles of amplitude in the range of 0.1 to 5.0 micrometers and a separation of their axes in the range of 0.01 to 1.0 micrometer and having an aspect ratio in the range of 0.01 to 10 micrometers.
U.S. Pat. No. 4,340,276 (Maffit) discloses a method for making a microstructure on the surface of an article, the method comprising the steps of depositing a discontinuous coating of a material exhibiting a low rate of sputter etching and differentially sputter etching the composite surface to produce a topography of pyramid-like micropedestals random in height and separation.
Oehrlein et al. in "Study of Sidewall Passivation and Microscopic Silicon Roughness Phenomena in Chlorine-Based Reactive Ion Etching of Silicon Trenches", J. Vac. Sci. Technol. B, 8, (6), November/December, 1990, pp. 1199-1211, teach patterned structures using photolithographic and reactive ion etching methods.
Floro et al. in "Ion-Bombardment-Induced Whisker Formation On Graphite", J. Vac. Sci. Technol. A, 1, (3), July-September, 1983, pp. 1398-1402, disclose graphite whisker-like structures produced by an ion bombardment process.
U.S. Pat. No. 4,252,865 (Gilbert et al.), teaches a solar energy absorbing surface, the surface characterized by having an array of outwardly projecting structural elements of relatively high aspect ratio and having effective lateral spacings which are or include those in the order of magnitude of wavelengths within the solar energy spectrum. The disclosed method for making the solar energy absorbing surface involves etching a sputtered amorphous semiconductor material (e.g., Ge).
U.S. Pat. No. 4,396,643 (Kuehn et al.), discloses a metal layer having a microstructured surface characterized by a plurality of randomly positioned discrete protuberances of varying heights and shapes. The microstructured surface is said to be useful as a radiation absorber.
Lee et al. in "Measurement and Modeling of the Reflectance-Reducing Properties of Gradient Index Microstructured Surfaces", Photo. Sci. and Eng., 24, (4), July/August, 1980, pp. 211-16, describe microstructured surfaces having structure-element dimensions comparable to the wavelength of visible light.
U.S. Pat. No. 4,148,294 (Scherber et al.), discloses a panel said to be capable of absorbing incident solar energy at a high rate and of radiating only a small portion of the absorbed energy, the panel comprising (a) a continuous metallic substrate consisting predominately of aluminum, (b) an anodized layer covering a face of the substrate and being integrally bonded thereto, the layer consisting predominantly of aluminum oxide, the layer having a surface directed away from the substrate and formed with a multiplicity of pores spaced apart 0.1 to 1 micrometer and having a diameter of 0.1 to 0.5 micrometer, and (c) a multiplicity of elongated metallic bodies respectively received in the pores and longitudinally projecting outward of the surface.
U.S. Pat. No. 4,155,781 (Diepers) teaches a method for manufacturing solar cells comprising growing semiconductor whiskers on a substrate, the method comprising (a) providing a substrate which favors growth or germination of whiskers, (b) depositing a plurality of localized areas of an agent in which the semiconductor material is soluble, (c) growing whiskers of the semiconductor material by means of the Vapor Liquid Solid (VLS) method at the areas, (d) doping the whiskers with one of p or n doping material, (e) subsequently thereto doping the surface region of the whiskers up to a depth which approximately corresponds to the diffusion length of the charge carriers pairs with the other of a p or n doping material.
U.S. Pat. No. 4,209,008 (Lemkey et al.) discloses a photon absorbing surface having an oriented microstructure consisting of at least two phases, a continuous metallic matrix phase and a discontinuous second phase selected from the group consisting of metals, metalloids and intermetallics, with the second phase having dimensions on the order of 0.001 to 10 micrometers and with the second phase being oriented substantially normal to the surface; the surface portion of the matrix phase having been removed so that the second phase protrudes in relief.